Manafort’s Lawyer Said to Brief Trump Attorneys on What He Told Mueller

In asserting that investigators were unnecessarily targeting Mr. Trump, Mr. Giuliani accused the prosecutor overseeing the Manafort investigation, Andrew Weissmann, of keeping Mr. Manafort in solitary confinement simply in the hopes of forcing him to give false testimony about the president.

But detention officials decide whether inmates serve in solitary confinement, according to law enforcement officials, and allies of Mr. Manafort have said he is there for his own safety.

A spokesman for Mr. Mueller’s office declined to comment. Mr. Weissmann is a longtime senior Justice Department prosecutor who specializes in prosecuting financial crimes and turning defendants into cooperating witnesses. His aggressive nature has earned him two competing reputations: Prosecutors view him as a relentless investigator who has overseen some of the Justice Department’s most complex investigations, but some defense lawyers say he is overly combative and will bend the facts to gain a conviction.

In his own recent Twitter attacks on the special counsel, the president seemed to imply that he had inside information about the prosecutors’ lines of inquiry and frustrations. “Wait until it comes out how horribly & viciously they are treating people, ruining lives for them refusing to lie,” Mr. Trump wrote on Tuesday.

Earlier this month, he tweeted: “The inner workings of the Mueller investigation are a total mess. They have found no collusion and have gone absolutely nuts. They are screaming and shouting at people, horribly threatening them to come up with the answers they want.”

Mr. Manafort’s legal team had long kept Mr. Trump’s lawyers abreast of developments in his case under a joint defense agreement. The president’s team has pursued such pacts as a way to monitor the special counsel’s inquiry. Mr. Giuliani said last month that the president’s lawyers had agreements with lawyers for 32 witnesses or subjects of Mr. Mueller’s 18-month-old investigation.

Defense lawyers involved in investigations with multiple witnesses often form such alliances so they can share information without running afoul of attorney-client privilege rules. But when one defendant decides to cooperate with the government in a plea deal, that defense lawyer typically pulls out rather than antagonize the prosecutors who can influence the client’s sentence. For instance, a lawyer for the president’s former national security adviser Michael T. Flynn withdrew last year from such an agreement with Mr. Trump’s lawyers before pleading guilty to a felony offense and agreeing to help the special counsel.